DE69918485T2 - Multi-layered skin, process for slip-casting of this skin and use of this skin - Google Patents

Description

AREA OF INVENTION

These Invention relates to a complex skin of the type which is suitable for open, decorative surfaces is used, and in particular a skin, in the slush-molding process made of a thermoplastic elastomer composition becomes. The invention includes as well as an object that contains the complex skin.

STATE OF TECHNOLOGY

It is known to be a Powder slush molding process using soft vinyl chloride resin powder carried out is going to be a big one Selection of skins produce, such as for objects in the automotive interiors such as dashboards, console containers, door panels etc. This method makes it possible to produce a skin which feels soft and which are curled and can be stapled. Furthermore, this method allows a high level Design freedom.

in the Difference to other molding processes, such as injection molding and molding, does not produce the powder slush molding process a certain shape under pressure. The powder flow behavior may not be sufficient to be evenly attached to effect on a shape with complex design. Preferably should the powder material have a sufficiently low melt viscosity, around during the time when the powder sticks to a mold without application melted by pressure to form a layer.

It is also desirable that the shaped skin by cooling the shape is easily removable.

In JP-A-07082433 proposes a masterbatch of polypropylene resin and a thermoplastic elastomer of a special styrene series in weight ratio from 70:30 to 30:70. The thermoplastic elastomer from the styrene series is selected from a styrene / ethylene-butylene / styrene block copolymer having a Styrene content less than or equal to 20 wt .-%, a styrene / ethylene-propylene / styrene block copolymer having a styrene content of less than or equal to 20% by weight and a hydrogenated one Styrene-butadiene random copolymer rubber having a styrene content less than or equal to 20% by weight. The thermoplastic elastomer The styrene series is easily miscible with the polypropylene resin. The obtained mixture is considered as for described the powder molding method suitable.

The Patent Application EP-A-0811657 describes a thermoplastic elastomer composition for powder slush molding process and a Process for the preparation of the mixture. The mixture consists of a polypropylene resin, a hydrogenated styrene-butadiene rubber, a process oil and an elastomer with very good oil absorption power.

The Patent Application EP-A-0796894 describes a polyolefin resin mixture and a coated product based on this mixture. The Polyolefin mixture includes a resin containing a modified polyolefin resin having at least a kind of functional group such as e.g. a hydroxy, one Carboxylic and a carboxylic anhydride group having. The application includes Also a be coated polyolefin resin mixture containing a molded Product of the polyolefin resin.

The Application WO-A-9733940 describes a thermoplastic elastomer blend and a powder and an article formed therefrom. The thermoplastic Elastomer mixture includes Polyolefin resin, an ethylene / α-olefin copolymer and an ethylene / α-olefin copolymer rubber. WO-A-9733940 describes the mixture as suitable for molding objects with excellent flexibility and flexibilities available to deliver.

The Application FR-A-2698311 describes a process for the preparation a structure covered with a skin, and laminates that to be obtained.

The mixture is suitable for forming a skin material because the hydrogenated styrene-butadiene random copolymer rubber can be finely dispersed in the polypropylene resin when the polypropylene resin is mixed with the hydrogenated styrene-butadiene random copolymer rubber. This results in a reduced deterioration of physicochemical properties. However, if this mixture is considered internal Layer of complex skin having an inner and an outer layer is used, oligomeric ingredients, a process oil, a stabilizer tend. and a catalyst in the mixture for bleeding on the surface of the skin, thus making the resulting skin viscous. The reason for this is the low oil absorbency of the hydrogenated styrene-butadiene random copolymer rubber.

If formed a transparent coating and thermally on the surface the outer layer the complex skin is applied so that a reinforcement of the same causes bleeding process oil, Stabilizing agent and catalyst in the inner layer together with oligomeric constituents therein over time at the surface, what possibly the adhesion of the complex skin to the underlying urethane foam deteriorated. Since the powder of the thermoplastic elastomer mixture, which determines the inner layer during the slush molding process is below the ambient temperature, the oligomers bleed Ingredients, the process oil, the stabilizer and the catalyst in the mixture the surface of the powder, which puts the powder in a viscous state. The mixture may cause a blockage over time the result that is the powder flow behavior deteriorated. The releasability of the skin can also be worsened become. The skin can be deformed during removal.

in the general have skins, those using standard thermoplastic elastomer blends are made, not both, a satisfactory adhesion to the form and a given Unmolding. Usually For example, the thermoplastic elastomer blends are modified to to improve mold release, while adhesion promoters and adhesives be applied to the mold to increase the adhesion. however The skin tends after such an adhesive treatment to the treated areas remain viscous, so that the skin obtained not can be stacked, for example, for storage. That's why one can considerable space would be required to store these skins.

The Patent application EP-A-0811657 (see Table 1) comprises a Skin, which is a first layer containing a polypropylene resin, a hydrogenated Styrene-butadiene random copolymer rubber, a process oil, an elastomer, this is the suitable process oil and having a mold release agent, the skin having an outer surface, which is suitable to be bound to a coating, and a inner surface, which is suitable bound to a core layer or a foam layer to become.

A Mixture of an elastomer, an olefinic polymer with active Hydrogen and a catalyst which is suitable, the isocyanate reaction to promote, is known as such from EP-A-0796894; and a multi-layered one Slush molding process is known from WO-A-9733940 and FR-A-2698311.

EP-A-0811657 comprises about that In addition, a method of providing a skin comprising the step producing a first layer which is a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil and a Contains mold release agents, in the slush molding process, the skin having an outer surface that is capable of being bound to a coating layer, and an inner surface which is suitable to a core layer or a foam layer to be bound.

The objective task, which is solved by the present invention, is a good adhesion between such a skin and a polyurethane layer applied thereto.

The The object is achieved by a multilayer skin according to claim 1, a method according to claim 11 and the use of the multilayer skin according to claims 17, 18, 20 and 21.

SUMMARY THE INVENTION

The The invention relates to a multilayer skin comprising an outer and having inner layer. The outer layer is achieved by using powder of a thermoplastic elastomer mixture, which is a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil and a mold release agent contains produced in a slush molding process. The inner layer is on the outer layer bound, she is through slush-molding process and is a mixture of an elastomer that is suitable is, the process oil to absorb an olefinic polymer with active hydrogen and a catalyst suitable for containing the isocyanate Promote reaction.

The inner layer also affects a multi-layered skin, which has an outer and having an inner layer. The outer layer is made by slush molding the powder of a thermoplastic elastomer mixture, the at least a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber Process oil, an elastomer capable of absorbing the process oil and a mold release agent comprises, manufactured. The inner layer is made by using a first and a second Powder produced in a slush molding process. The first powder consists of a thermoplastic elastomer mixture, which is a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, and a Elastomer, which is suitable to absorb the process oil contains. The second powder an elastomer capable of absorbing the process oil is an olefinic one Polymer with active hydrogen and a catalyst that is suitable is to promote the reaction comprising isocyanate.

The The invention also relates to an article comprising one of a synthetic one Resin-made core layer, a multi-layered skin with a inner and an outer layer bonded to the inner layer and a foam layer between the core layer and the multilayer Having skin. The foam layer is on the multilayered skin and the core layer bound. The outer layer of the multilayered Skin is made by slush molding of the powder of a thermoplastic elastomer mixture consisting of a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil, and a Mold release agent is made in a slush molding process. The inner layer of the multilayer skin is made of an elastomer, that is suitable, the process oil to absorb an olefinic polymer with active hydrogen and a catalyst suitable for containing an isocyanate Promote reaction.

The The invention also relates to an article comprising one of a synthetic one Resin-made core layer, a multi-layered skin with a inner and an outer layer bonded to the inner layer and a foam layer between the core layer and the multilayer Having skin. The foam layer is on the multilayered skin and the core layer bound. The outer layer of the multilayered Skin is made by using powder of a thermoplastic elastomer blend, consisting of a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil, and a Mold release agent is made in the slush molding process. The inner layer is made by using a first and a second Powder in the slush molding process produced. The first powder consists of a thermoplastic Elastomer blend comprising a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, and an elastomer capable of absorbing the process oil. The second powder is an elastomer capable of absorbing the process oil an olefinic polymer with active hydrogen and a catalyst, which is suitable for promoting an isocyanate-comprising reaction.

The The invention also relates to a multilayered skin with an internal one and an outer layer, each made from a powder in a slush-molding process has been. The powder in the outer layer is a thermoplastic blend comprising a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer, that is suitable, the process oil and having a mold release agent. The inner layer comprises a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil is an olefinic one Polymer with active hydrogen and a catalyst that is suitable is to promote a reaction comprising isocyanate.

The Invention relates to this a multi-layered skin with an inner and an outer layer, each made of powder in a slush molding process. The powder in the outer layer is a thermoplastic blend comprising a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer, that is suitable, the process oil and having a mold release agent. The inner layer is achieved by using a first and a second powder in the slush molding process produced. The first powder consists of a thermoplastic Elastomer blend comprising a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, and an elastomer capable of absorbing the process oil. The second powder consists of a thermoplastic elastomer mixture, a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil is an olefinic one Polymer with active hydrogen and a catalyst that is suitable is to promote a reaction comprising isocyanate contains.

The invention further relates to an article comprising a core layer made of a synthetic resin, a multilayered skin having an inner and an outer layer, each of powder in the Slush molding process can be produced, and having a foam layer between the core layer and the multilayer skin. The foam layer is bonded to the core layer and the multi-layered skin. The outer layer is slush molded from powder composed of a thermoplastic elastomer mixture comprising a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil, and a mold release agent Method produced. The inner layer is made of powder composed of a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil, an olefinic polymer having active hydrogen and a catalyst which is suitable Isocyanate to promote comprehensive reaction consists of produced by the slush molding process.

The inner layer may further comprise a mold release agent.

The Foam layer can be a polyurethane foam.

The Core layer may be an olefinic resin.

In a form shows the outer layer a surface and a coating is formed on this surface of the outer layer.

The Elastomer capable of containing the process oil in one or both of the inner and the outer layer, may be an ethylene-octene copolymer.

The relationship from the first to the second powder may be 1: 5 to 5: 1.

The The invention further relates to the use of a thermoplastic Elastomer mixture for forming an inner layer of a multilayered Skin that has an inner and an outer layer owns, in the slush-molding process. The thermoplastic elastomer mixture consists of a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a Process oil, an elastomer capable of absorbing the process oil, an olefinic one Active hydrogen polymer, a catalyst that is suitable is to promote a reaction comprising isocyanate, and a mold release agent.

The Elastomer, which is suitable to absorb the process oil, can Ethylene-octene copolymer with a long-chain branched structure be.

SHORT DESCRIPTION THE DRAWINGS

1 shows a perspective view of an auto dashboard with a complex skin contained therein;

2 shows an enlarged view of the cross section of the Autoarmarturenbretts along the line 2-2 in 1 and

3 shows an enlarged view of the cross section of a padded part of the car dashboard 1 and 2 ,

DETAILED DESCRIPTION OF THE DRAWINGS

An inventive Armarturenbrett is with 10 referred to in the figures and consists of a soft, padded part 12 and a hard part 14 , The surface of the soft part 12 is determined by a complex / multi-layered skin 16 with grain pattern consisting of an inner layer 18 and an outer layer 20 was formed. A core layer 22 lies under the complex skin 16 and is made of a synthetic resin. A foam layer 24 , such as a polyurethane foam, is located between and is at the core layer 22 and the complex skin 16 in the soft part 12 bound. In the hard part 14 the complex skin sticks 16 directly on the core layer 22 ,

The outer layer 20 is characterized by the use of a thermoplastic elastomer blend powder comprising at least one polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil, and a mold release agent in the slush molding process. Process produced.

The inner layer 18 is slushed by the use of a thermoplastic elastomer blend powder comprising at least one elastomer capable of absorbing the process oil, an olefinic active hydrogen polymer, and a catalyst capable of promoting the isocyanate reaction -Molding process produced. The inner layer 18 For example, by use of a powder of a thermoplastic blend containing at least a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil, an olefinic active hydrogen polymer, and a catalyst is capable of promoting an isocyanate-containing reaction contains, be formed in a slush molding process. An internal release agent may be added to the latter thermoplastic blend.

Because the outer layer 20 Contains a release agent, the removability of the outer layer 20 be improved from a mold. The internal adhesion of the inner layer 18 at the core layer 22 and the foam layer 24 can be improved by an agent which enhances the adhesion of the thermoplastic to the elastomer.

An optional coating 26 can on the outer surface of the outer layer 20 be formed. The coating 26 may be a urethane or an acrylic urethane and reinforces the surface of the outer layer 20 to avoid damage to it. Preferably, a surface treatment agent is formed on the outer layer 20 used the adhesion of the coating 26 on the surface of the outer layer 20 to improve.

Any polypropylene resin, including polypropylene homopolymer and a block or random copolymer of the polypropylene with alpha-olefin, may be present either in the outer layer 20 alone or in both, the outer layer 20 and the inner layer 18 , are used. A block or random copolymer having ethylene as the α-olefin is preferred in view of the resulting flexibility of the molded product. In a no-pressure powder slush molding process, the polypropylene resin should have a melt flow rate (MFR) of 20 g / 10 min or higher measured at a temperature of 230 ° C under a load of 2.16 kgf in accordance with JIS K7210.

The Polypropylene resin described above is a polymer in which the primary Chain is split due to heat or oxidation. The resin has different properties of polyethylene by networking and thereby a thermoset is. The primary chain is made with an organic Peroxide cleaved, which causes a decrease in molecular weight.

The hydrogenated styrene-butadiene random copolymer rubber (H-SBR) can only be used in the outer layer 20 or in both, the outer layer 20 and the inner layer 18 be used; and it has good miscibility with the polypropylene resin. When kneaded with the polypropylene resin, the copolymer rubber becomes more flexible so that a thermoplastic elastomer composition which is flexible and less whitened can be developed. The styrene content of the hydrogenated styrene-butadiene random copolymer rubber is preferably less than or equal to 30% by weight. To produce a skin with improved flexibility, the styrene content is about 5 to 15% by weight.

H-SBR differs from styrene / ethylene-butylene / styrene (SEBS) as a block polymer in that the Styrene-butadiene hydrogenated with styrene and butadiene randomly copolymerized is. Typical products included those of the Dynaron series manufactured by JSR Co., Ltd. become.

The relationship from polypropylene resin to H-SBR, which are mixed together is between 80:20 and 20:80 wt .-%. When the polypropylene resin exceeds this ratio, the resulting skin becomes stiff. If the resin falls below this ratio, is the tear strength reduced.

The elastomer component in the mixture is suitable, the process oil, which alone the outer layer 20 or both, the outer layer 20 and the inner layer 18 , is added to absorb. This aims to reduce the melt viscosity and additionally reduces the hardness of the skin, which improves flexibility. The process oil is used in rubbers and is characterized as a series of paraffins, a series of naphthenes and a range of aromatic oils. Preferably, the process oil from the series of paraffins is used because of its miscibility with the elastomer component. The process oil is preferably added in an amount of 5 to 200 parts by weight based on the elastomer suitable to absorb the process oil. When the process oil of more than 200 parts by weight is added, the tear strength is deteriorated. If the process oil is below 5 parts by weight, the melt viscosity can not be reduced, resulting in a stiff skin.

That in both layers, the outer layer 20 and the inner layer 18 Elastomer is miscible with the poly propylene resin and tends to absorb the process oil and the oligomeric components in the composition. The elastomer may, for example, be a styrene series block copolymerized thermoplastic elastomer such as a styrene / ethylene-butylene / styrene block copolymer (SEBS) and styrene / ethylene-propylene / styrene block copolymer (SEPS), olefin crystal / ethylene-butylene / olefin crystal. Block copolymer (CEBC), ethylene-propylene rubber (EPR) and ethylene-octene copolymer (POE).

The POE is a polymer produced by the use of a single-site catalyst, the main one from metallocene compounds and having a reactive site in the molecule, which produces similar species. Usually the POE has a long-chain, branched structure with a narrow Range of molecular distribution and a uniform composition distribution and a lower content of low molecular weight oligomers or Wax. Compared with the ethylene-propylene-nonconjugated diene copolymer (EPDM), the POE has a sufficiently high flowability and dispersibility when it is mixed with the polypropylene so that it is easily in the polypropylene resin is finely dispersible. Therefore, POE is a suitable material for the slush molding process. additionally differs the POE in the molecular structure of usual linear polymers obtained by the use of Ziegler-Natta catalysts produced, such as conventional ethylene-propylene rubber, which is produced by copolymerization of ethylene and propylene becomes.

The SEBS described above is obtained by hydrogenation of the styrene-butadiene / styrene block copolymer (SBS) manufactured, such as products of the Crayton G series, the manufactured by Shell Chemical Co., Ltd., and products Toughtech H series manufactured by Asahi Chemicals Ind. Co., Ltd. become. SEBS with a higher Styrene content can a higher one Gain strength, but then have a reduced flexibility. From these SEBS can be difficult to develop a soft, leaf-like Object because the hard styrene segment in the SEBS becomes contiguous, if the SEBS during of the slush molding process melts. Consequently, the styrene content becomes preferably kept below 40 wt .-%.

SEPS is prepared by hydrogenation of a styrene / isoprene / styrene block polymer. The SEBS may be, for example, SEPTON, a product manufactured by Kuraray, Co., Ltd., its. Similar how SEBS gets the flexibility diminished as the styrene content increases. The styrene content is preferably below 40% by weight.

Compared with H-SBR is the elastomer capable of absorbing the process oil not miscible with polypropylene resin. If it is with the polypropylene resin is kneaded and added to the polypropylene resin is the elastomer in an order of magnitude of μm units which probably reduces the tear strength caused. When H-SBR and the process oil are added to the polypropylene resin, can the oligomeric compounds in the mixture due to the low oil absorbency of the H-SBR on the surface bleed out, so that the surface becomes viscous. The elastomer powder made using the resulting Mix for The powder-slush molding process has been pulverized as well become viscous, as a result of which blocking occurs, the deterioration of the powder flow behavior and a low Demouldability of the resulting skin results. If the elastomer, that is suitable, the process oil which is added to the resin absorbs the elastomer the oligomeric components and the oil in the mixture so that the elastomer prevent their bleeding to the surface can.

The Elastomer capable of absorbing the process oil becomes 20 added to 250 parts by weight per 100 parts by weight of H-SBR. If the elastomer is added in less than 20 parts by weight, For example, the elastomer may include the oligomeric compounds in the mixture or the oil do not absorb adequately. If the elastomer in over 250 By weight, the elastomer may be poor in the polypropylene resin to be dispersed, which is the tear strength deteriorated.

The inner mold release agent, either in the outer layer 20 alone or in both, the outer layer 20 and the inner layer 18 may include silicone oil such as dimethylsiloxane, methylhydroxypolysiloxane, methylphenylpolysiloxane, higher fatty acids, higher fatty acid amides and higher fatty acid salts. The mold release agent is preferably in the outer layer 20 in an amount of 0.1 to 5.0 wt .-% added. Below 0.1% by weight, the mold release agent can not sufficiently improve mold releasability. Above 5.0% by weight, the adhesion to the inner layer becomes 18 adversely affected.

The mold release agent becomes in the inner layer 18 preferably added in an amount of 0.1 to 1.0 wt .-%. Below 0.1% by weight, the mold release agent may bleed the oligomeric compounds in the Mixture, the process oil, the stabilizer and the catalyst on the surface does not sufficiently prevent. Above 5.0% by weight, adhesion to the foam layer may no longer be adequate.

The olefinic polymer with active hydrogen for the inner layer 18 may include an acid-modified polypropylene resin, a hydroxyl group-containing polypropylene resin, a hydrolyzate of an ethylene-vinyl acetate copolymer, a carboxyl-terminated polybutadiene, a hydroxyl-terminated polybutadiene, a hydrogenated product of a carboxyl-terminated polybutadiene, a hydrogenated polybutadiene-terminated polybutadiene , an acid-modified styrene / ethylene-butylene / styrene block copolymer, ethylene-methacrylate copolymer and ethylene-acrylate copolymer. In the example (described herein), an OH-modified polyolefin is used.

The Polymer is preferably added in an amount of 2 to 20% by weight. Under 2% by weight, the polymer can not effectively improve the adhesive properties. Over 20% by weight can the tear strength undesirably be reduced.

The catalyst capable of promoting an isocyanate-comprising reaction in the inner layer 18 can organic tin compounds, such as. B. dibutyltin dilaurate and dibutyltin distearate, tertiary amine compounds such as tetraalkylethylenediamine and N, N'-dialkylbenzylamine, fatty acid salts such. Cobalt naphthenate and zinc stearate, as well as carboxylic acid salts of the alkali metals.

This catalyst is used in amounts of from 0.01 to 2 parts by weight of the thermoplastic elastomer composition consisting of the polypropylene resin, the hydrogenated styrene-butadiene random copolymer rubber, the elastomer capable of absorbing the process oil, and the olefinic polymer having active hydrogen. added. Below 0.01 parts by weight, the adhesion of the inner layer 18 to the foam layer 24 be inadequate. Over 2 parts by weight may result in disadvantageous bleeding on the surface.

Typical thermal stabilizers for use in polyolefins may be in the outer layer 20 and the inner layer 18 be used. A combination of phenolic antioxidants with phosphite series antioxidants can be used. Radical scavengers from the sterically hindered amine series and the benzotriazole series can be used as light stabilizers.

Usual organic or inorganic pigments suitable for the olefin series are, can be used. radical scavengers from a series of sterically hindered amines and a number of benzotriazoles can be considered as Light stabilizer can be used.

Usual organic or inorganic pigments suitable for the olefin series are, can be used. Lubricants such. B. metal salts of fatty acids and fillers such as As calcium carbonate and the benzotriazole series as a light stabilizer can be used.

According to the invention becomes an organic peroxide of a mixture of the polypropylene resin, the process oil, the elastomer capable of absorbing the process oil and the inner one Mold release agent or a mixture of the polypropylene resin, the olefinic polymer with active hydrogen, the elastomer, the suitable is the process oil to absorb, and the process oil added. The resulting mixture is kneaded together with heating. The organic peroxide splits the primary chain of the polypropylene resin so that that resulting Polypro pylenharz a lower molecular weight and has a higher melt flowability. The organic peroxide increases the melt flow of the obtained thermoplastic elastomer mixture. The organic peroxide is not used as a crosslinking agent. The thermoplastic Elastomer compound produced by the kneading process under heating was included no appreciable amounts of organic peroxide, as the organic Peroxide is thermally decomposed.

The Organic peroxide includes those substances commonly in crosslinked rubbers and resins, e.g. Diacyl peroxide, peroxyester, diallyl peroxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, Dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) -hexane-3, 1,3-bis (tert-butylperoxy-isopropyl) benzene and 1,1-dibutylperoxy-3,3,5-trimethylsiloxane. The organic peroxide preferably has a half-life of one minute due to the thermal decomposition at 150 to 200 ° C.

During the kneading process, which proceeds to 150-200 ° C during heating, the organic peroxide splits the primary chain of the polypropylene resin to reduce the molecular weight and thereby improve the melt flow behavior of the thermoplastic elastomer blend. The organic Peroxide is added in amounts of from 0.02 to 5.0% by weight, based on the thermoplastic elastomer mixture. Below 0.02 wt%, the ability of the mixture to decompose the primary chain of the polypropylene resin by decomposition may be sufficiently low that the organic peroxide can not effectively increase the melt flow properties of the thermoplastic elastomer composition. Above 5% by weight, the decomposition may become so excessive that the article produced in the powder slush molding process has some poor mechanical properties including a low tear strength.

The Blends are mixed by: mixing dry one given mixture using a V-mixer, a tumbler or a Henschel mixer; feeding the obtained mixed Mixture of a raw material hopper while of the outflow of the process oil from an outlet opening; and melt-kneading the obtained mixture using a Twin screw extruder at a temperature of 120 - 150 ° C to a Pelleting of the mixture to effect. The mixture can be in a kneaded in two ways.

By The addition of the process oil to the elastomer component H-SBR and the elastomer which is suitable is, the process oil to absorb, and the kneading of the mixture using a seal-type kneader and a Branbury mixer becomes the mixture pelletized. After that, the organic peroxide and the others Mixing aids mixed with the pellets and the polypropylene resin. By using a single or twin screw extruder in the temperature range of 120 to 150 ° C, the mixture can be pelleted become.

The melt (MFR), which are based on the melt flow viscosity of the obtained Pellets indicates, is preferably at 50 g / 10 min or higher 250 ° C below a load of 0.325 kgf according to JIS K7210. Below this value is the melt flow behavior the mixture is reduced so that the Training of small holes (pin holes) in the skin is likely to occur.

The Pellets made from the mixture are used of a turbo-turbo type, such as. a turbo mill, a needle mill or a hammer mill, finely ground. The pellets can to be ground while they through the use of liquid Nitrogen are frozen. Depending on the mixture, the molten resin with the means of a spray or Disk atomizer sprayed and cooled to cause pulverization of the resin.

ground Material that passes through a sieve with the mesh size of 1000 microns can and a mean grain size of 100 up to 800 μm is collected. This becomes an organic or inorganic Adjuvant which modifies the powder properties, added and mixed. The resulting mixture is used in the powder slush molding process.

The mixed mixtures for use in the layer 18 are a mixed powder containing a first powder which is a thermoplastic elastomer composition containing at least the polypropylene resin, H-SBR, the process oil, and the elastomer capable of absorbing the process oil, and a second powder; which is a thermoplastic elastomeric admixture for adhesion and which comprises at least the elastomer capable of absorbing the process oil, the olefinic active hydrogen polymer and the catalyst capable of promoting the isocyanate reaction.

The thermoplastic elastomer blends are as described above pulverized. The weight ratio from first to second powder is 1: 5 to 5: 1. If the proportion of the second powder is below this range, it can an insufficient one Liability result. If the amount of powder is larger, can the tear strength the resulting skin undesirably be reduced.

The mixed blends for use in the inner layer 18 are a blend of a first powder of a thermoplastic elastomer blend containing at least the polypropylene resin, H-SBR, the process oil, the elastomer capable of absorbing the process oil and an internal mold release agent, and a second thermoplastic containing powder Elastomeric admixture for adhesion, which comprises at least polypropylene resin, H-SBR, the process oil, the elastomer capable of absorbing the process oil, and an internal mold release agent, and a second powder which is a thermoplastic elastomer blend for adhesion, and which is at least Polypropylene resin, H-SBR, the process oil, the elastomer capable of absorbing the process oil, the olefinic polymer having active hydrogen and a catalyst capable of promoting the isocyanate-comprising reaction. The thermoplastic elastomer blends are pulverized as described above. The weight ratio of the first powder to the second powder in the mixture is between 1: 5 and 5: 1. If the second powder in a lower A sufficient liability can not be realized. If the second powder is present in a larger amount than in the range, the tear strength of the obtained skin is undesirably lowered.

One inner mold release agent may be added to the powder of the thermoplastic elastomer composition be added to the liability.

The powders of the elastomer mixtures described above are used in the slush molding process. Taking advantage of gravity, the powders are in excess of the melting point of the mixture for the outer layer 20 given heated form. By reversing the mold after a predetermined period of time, the excess mixture can be collected in a recovery tank. The mixtures adhere in layers to the surface of the mold and merge with time to form an outer layer of 0.3 to 1.0 mm thickness.

The mixtures for use in the inner layer 18 be taking advantage of gravity against the formed outer layer 20 directed. The mold may then be reversed after a predetermined period of time, with the excess of the mixture collected in a recovery container. The inner layer 18 melts with time to form a layer with a thickness of 0.1 to 0.5 mm. By cooling the mold, the skin obtained 16 be removed from the mold and the above procedure can then be repeated.

The Mold can be heated by placing in a recirculating or hot air oven is provided. The temperature of the mold can be in the oil circulation furnace through piping be controlled, which cause only the heating through the mold surface. When using a hot air oven The shape can be from both the mold surface and the back an object which is molded, heated. The hot air will preferably over 300 ° C held. The conditions are being managed that she no thermal oxidation and no deterioration of the backside cause a molded object.

The Hot air method is for producing multiple layers, e.g. two or three, in the pluver-slush-molding process successful. In particular, a first powder in a heated Shape as the outermost layer be used in the slush molding process, followed by a second Powder attached to the first powder in the semi-molten state can be. Then a third powder is slush-molding used. The resulting layers are then heated and melted. In this process, the heat transfer be inadequate if the mold is heated just above its surface becomes. That is why a hot air oven process prefers.

The complex skin 16 formed in the above process is adhered to a mold such that the outer layer 20 can touch the mold surface. The core layer 22 , which may be a synthetic resin such as polypropylene, ABS or polystyrene, is arranged in a different form. The foam layer 24 which may be a foam raw material, such as polyurethane, is leveled between the molds to attach to the complex skin 16 and the core layer 22 to adhere to a molded object 10 manufacture.

A powder that is used to make a complex skin 16 can produce a good flexibility according to the invention. At least in part, due to the blocking of the bleeding out of the oligomeric ingredients, the process oil, the stabilizers and the catalysts in the inner layer, the complex skin can 16 even when effectively adhering to a foam layer when the complexed skin 16 and items made from it are stored for a long time.

Special, Inventive examples and their properties will now be with respect to comparative examples described.

INVENTIVE EXAMPLES 1 TO 5 AND COMPARATIVE EXAMPLES 1 AND 2

Outer layers be as in Table 1 for the examples of the invention 1 and 2 and Comparative Example 1 and as in Table 2 for the inventive examples 3 to 5 and the comparative example 2 shown.

For each example, a polypropylene resin (PP resin), an elastomer capable of absorbing the process oil (POE), an internal mold release agent (calcium stearate), and an organic peroxide were dry blended in a tumbler. While supplying the obtained mixture from the hopper of a twin screw extruder (PCM45 manufactured by Ikegai Steel Industries) and flowing the process oil from an outlet port, the mixture was kneaded at a cylinder temperature of 210 ° C and a screw revolution of 300 rpm. H-SBR, a process oil, a phenolic antioxidant and an (anti) oxidant of the phosphite series were dry mixed together. While simultaneously feeding into the resulting mixture from an outlet port, the mixture was kneaded together under the same conditions and then extruded and pelletized. In the tables, the numbers in brackets indicate the amount of material in parts by weight that was added the second time.

To the filling and grinding in liquid Nitrogen dipped pellets in a turbo mill T250-4J (manufactured by Turbo Industries, Co.) were particles containing a sieve with mesh size of 1000 μm passed, collected.

Under the above for the outer layers conditions described, the powders for the outer layers were washed twice Using a twin screw extruder, kneaded, extruded and pelletized. The obtained pellets were immersed in liquid nitrogen and in a turbo mill T250-4J (manufactured by Turbo Industries, Co.) for milling. Powder, capable of passing through a 1,000 μm screen, were used in the inner layers. The numbers in the Brackets indicate the amount of material in parts by weight, added the second time has been.

The Powder for the outer layers were in the slush molding process used. An outer layer, which has a thickness of 0.6 mm, was in a slush molding process formed. A plate with grain pattern and with the dimensions 150 mm × 150 mm × 3 mm was heated to 250 ° C in an oven heated. About 800 g of the outer layer powder was for about 10 Seconds applied so that the powder could adhere to the plate. The powder, which was not melted and did not adhere, became away. The obtained plate was heated in an oven at 300 ° C for 60 seconds heated up for a long time.

On the outer layer were about 800 g of the powder for the inner layer applied to a layer for 10 seconds Form with about 0.2 mm thickness. The layer was in an oven at 300 ° C Melted for 60 seconds and then removed from the oven. dannach The resulting layer was cooled in water to separate from the To enable form wherein the obtained skin had a thickness of about 0.8 mm.

The surface the outer layer was treated with a surface treatment agent called Leatheroid LU-775SP, that of Dainiti Fine Chemicals, Co., Ltd. was prepared, sprayed. Subsequently was sprayed a transparent coating of the urethane series. The outer layer was in an oven at 80 ° C 30 minutes in the heat dried.

The obtained skin was tested in its adhesion properties as follows. A Iron plate with dimensions 340 mm × 200 mm × 12 mm and a recess of 300 mm × 200 mm × 8 mm was used as a mold and in an oven at 40 ° C heated. The skin was placed on the bottom of the well. Dannach were About 100 g of a mixed raw material of a semi-rigid urethane foam poured thereon. The well was then immediately with an aluminum plate sealed, the resulting assembly in an oven at 40 ° C for 4 minutes was heated to produce a laminate of the skin and the urethane foam. For the exam became a piece with 25 mm width and 150 mm length cut out.

at a tensile rate of 200 mm / sec became the 180 ° -hardness strength and the adhesion state tested between the skin and the urethane foam. Adhesive strength above 5 N / 35 mm is indicated in the tables with a "Θ" 1 and 5 N / 25 mm is marked with an "O." The adhesive strength below 1 N / 25 mm is indicated by the symbol "X".

Of the Adhesive state is expressed as follows. The cohesive failure (cohesive failure) of the total urethane foam is expressed as 100. Of the cohesive failure part of it is expressed as a percentage (%) of that part. Of the Adhesive failure (interfacial failure) between the interfaces of the entire structure is called interfacial deduction designated.

The exam the adhesive property of using such a skin, was carried out after the coating of the surface.

For the melt viscosity was the melt flow rate at 230 ° C measured under a load of 2.16 kgf according to JIS K7210. These Results are shown in Table 1 for the examples of the invention 1 and 2 as well as for Comparative Example 1 and in Table 2 for the inventive examples 3 to 5 as well as for Comparative Example 2 is shown.

By Use of a powder tester (manufactured from Hosokawa Micron Co.) became the test of powder property by measuring the angle of repose a powder mixture with an added excipient which has the powder property modified, and a powder mixture after the molding of 20 Sheet or more performed.

As for the inventive examples has been shown, the releasability of the skin is high and the adhesive strength the inner layer of the skin to the urethane foam is similarly high.

Even after annealing the coated surface, the inner layer retained to which the internal release agent of the silicone series was added, the good adhesion to the urethane foam and also their adhesive strength and adhesion condition The urethane foam was maintained after aging for several days. Likewise the powder properties: the powder on the side of the inner Layer to which the silicone silicone inner mold release agent added was maintained the powder flowability.

INVENTIVE EXAMPLES 6 TO 8 AND COMPARATIVE EXAMPLES 3 AND 4

The Mixtures for the outer layer are shown below in Table 3.

In In any case, the mixtures were under the same condition as she for the examples of the invention 1 to 5, kneaded together and then extruded and pelleted. After the subsequent grinding in liquid nitrogen dipped pellets in a turbo mill T250-4J (manufactured by Turbo Industries, Co.) were particles containing a sieve with a mesh size of 1000 μm passed, collected.

For the inner one Layers were the blends of Table 3 once in a twin-screw extruder kneaded under the same conditions as for the outer layers and subsequently extruded and then pelleted. After the subsequent grinding in liquid Nitrogen dipped pellets in a turbo mill T250-4J (manufactured by Turbo Industries, Co.) powders were collected containing a sieve a mesh size of 1000 microns passed.

The Powder for the outer layers were then used in the slush molding process. Under the same Conditions as used in Examples 1 to 5 according to the invention were, a slush-molding process was carried out to an outer layer with a thickness of 0.6 mm. On the outer layer were about 800 g of a powder for the inner layer applied to a layer for 10 seconds with a thickness of 0.2 mm. Then the shift became in an oven at 300 ° C 60 Melted for a few seconds. Then the layer was removed from the oven, cooled in water and taken out of shape to a skin with a thickness of about 0.8 mm.

The Resilience of the skin was assessed by sight and was considered good (O) or weak (X).

The exam the adhesive properties were determined as follows. An iron plate with the dimensions 340 mm × 200 mm × 12 mm and a recess of 300 mm × 200 mm × 8 mm was used as a mold and in an oven at 40 ° C heated. The skin was placed on the bottom of the well. dannach About 100 g of a mixed raw material was semi-rigid Urethane foam poured on it. The well was then immediately sealed with an aluminum plate, the arrangement obtained in an oven at 40 ° C for 4 minutes was heated to a laminate of the skin and the urethane foam manufacture. One piece with 25 mm width and 150 mm length was cut out of this laminate and used for testing.

at a tensile rate of 200 mm / sec became the 180 ° -hardness strength and the adhesion state examined between the skin and the urethane foam. The adhesive strength over 5 N / 25 mm is filled with a Circle (Θ) specified. The adhesion between 1 and 5 N / 25 mm is with an unfilled circle (O) indicated. The adhesion under 1 N / 25 mm is indicated by an "X".

The Adhesive strength is designated as follows. The cohesive failure (cohesive failure) of the entire urethane foam is with is with an unfilled one Circle (O). The cohesive failure (cohesive failure) of a part of it comes with an unfilled triangle (Δ). Of the Adhesive failure (interfacial failure) between the interfaces of the entire structure is denoted by the symbol "X".

For the melt viscosity was the melt flow rate at 230 ° C measured under a load of 2.16 kgf according to JIS K7210.

These Results are shown in Table 3. The examples of the invention show that the mold release the skin is very good and that the Adhesive strength of the inner layer of the skin to urethane very high is.

The The foregoing disclosure of specific embodiments is intended to the broad, to explain concepts contained in the invention.

Claims (21)

Multilayer skin ( 16 ) comprising an outer layer ( 20 ) comprising a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil, and a release agent; and an inner layer ( 18 ), which are attached to the outer layer ( 20 ), the inner layer ( 18 ) an elastomeric mixture suitable for absorbing the process oil, an olefinic polymer having active hydrogen and a catalyst suitable for promoting reactions with isocyanates, wherein the outer layer ( 20 ) comprises a polypropylene resin, wherein the outer layer ( 20 ) has an outer surface suitable for coating ( 26 ), and wherein the inner layer ( 18 ) is adapted to a core layer ( 22 ) or a foam layer ( 24 ) to be bound. Multilayer skin ( 16 ) according to claim 1, wherein the elastomer suitable for absorbing the process oil is present in at least one of the inner layers ( 18 ) and outer layers ( 20 ) an ethylene-Oc thene copolymer. Multilayer skin ( 16 ) according to claim 1, wherein the inner layer ( 18 ) comprises a release agent. Multilayer skin ( 16 ) according to claim 1, wherein the coating ( 26 ) to the outer surface of the outer layer ( 20 ) is bound. Multilayer skin ( 16 ) according to claim 1, wherein the multilayer skin ( 16 ) a core layer ( 22 ) comprising a synthetic resin and a foam layer ( 24 ) between the core layer ( 22 ) and the multilayer skin ( 16 ), wherein the foam layer ( 24 ) to the multilayer skin ( 16 ) and the core layer ( 22 ) is bound. Multilayer skin ( 16 ) according to claim 5, wherein the foam layer ( 24 ) Polyurethane foam. Multilayer skin ( 16 ) according to claim 5, wherein the core layer ( 22 ) comprises an olefinic resin. Multilayer skin ( 16 ) according to claim 5, wherein the elastomer which is suitable for absorbing the process oil is present in at least one of the inner layers ( 18 ) and the outer layers ( 20 ) comprises an ethylene-octene copolymer. Multilayer skin ( 16 ) according to claim 5, wherein the inner layer ( 18 ) comprises a release agent. Multilayer skin ( 16 ) according to claim 5, wherein the outer layer ( 20 ) a surface and a coating ( 26 ) on the surface of the outer layer ( 20 ) having. Method for forming a multilayer skin ( 16 ) comprising the steps of: producing an outer layer ( 20 ) in the slush molding process, wherein the outer layer ( 20 ) a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, an elastomer capable of absorbing the process oil, and a release agent; and slush molding and binding of an inner layer ( 18 ) to the outer layer ( 20 ) to a multilayer skin ( 16 ), wherein the inner layer ( 18 ) a mixture of an elastomer suitable for absorbing the process oil, an olefinic polymer having active hydrogen and a catalyst suitable for promoting reactions with isocyanates, and wherein the outer layer ( 20 ) has an outer surface suitable for coating ( 26 ) and the inner layer ( 18 ) is adapted to a core layer ( 22 ) or to a foam layer ( 24 ) to be bound. Method according to claim 11, wherein the elastomer capable of absorbing the process oil Ethylene-octene copolymer with a long-chain, branched structure includes. A method according to claim 11, wherein a first powder and a second powder are slush-molded to form a multilayered skin ( 16 ) to build. Method according to claim 13, wherein the weight ratio of the first powder to the second powder is 1: 5 to 5: 1. Method according to claim 14, wherein the first powder is a thermoplastic elastomer composition comprises a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil and an elastomer capable of absorbing the process oil, and wherein the second powder is an elastomer capable of absorbing the process oil an olefinic polymer with active hydrogen and one for the promotion Catalyst suitable for isocyanate reactions. A method according to claim 11, wherein the inner layer ( 18 ) further comprises a release agent. Use of a multilayer skin according to claim 1 in a process in which a coating ( 26 ) on the outer surface of the outer layer ( 20 ) is formed after first a surface treatment agent on the outer surface ( 20 ) was applied to the adhesion of the coating ( 26 ) on the surface of the outer layer ( 20 ) to improve. Use of a multilayer skin according to claim 1 in a process comprising the step of bonding a polyurethane foam layer ( 24 ) to the multilayer skin ( 16 ) and the core layer ( 22 ), wherein the foam layer ( 24 ) between the core layer ( 22 ) and the inner layer ( 18 ) of the multilayer skin ( 16 ) lies. Use of a multilayer skin in a method according to claim 18, in which the core layer ( 22 ) comprises an olefinic resin. Use of a multilayer skin according to claim 1 in a process in which a coating ( 26 ) on the outer surface of the outer layer ( 20 ) is formed. Use of a multilayer skin according to claim 1 in a process in which the elastomer which is suitable, the process oil to absorb an ethylene-octene copolymer having a long-chain, branched structure includes.